NEW YORK (Reuters) – Wall Street plunged in a broad sell-off on Friday as China and the United States traded their latest salvos in a prolonged trade war, spooking investors and erasing slight gains following a generally positive speech by U.S. Federal Reserve chair Jerome Powell.

All three major U.S. stock indexes turned sharply lower, setting a course for their fourth consecutive weekly declines after President Donald Trump tweeted that U.S. companies should “immediately start looking for an alternative to China.”

Trump pressed American companies to leave China in response to an earlier announcement from Beijing that it would impose a new round of retaliatory tariffs on an additional $75 billion in U.S. goods, upping the ante in an acrimonious trade war that has roiled markets for months and shown little sign of abating.

“It is mind-boggling,” said Ken Polcari, managing principal at Butcher Joseph Asset Management in New York. “On one day (Trump) tells you everything is going great with China and today he is saying everyone get out of China.”

I never want to hear from any pundits saying Bernie can’t do anything if elected because Congress will oppose him. Trump has amply shown what sort of power a president has and can exercise if said President cares to do so.